Field of the Invention
The invention relates to a structure of a network plug, and more particularly to a compensation structure for electrical characteristics of a network plug without complicated metal sheets and circuits that are difficultly formed on PCB.
Description of the Related Art
A network cable usually includes eight core wires internally. The network cable is configured to extend through a jacket to enter a network plug. The core wires are peeled and electrically connected to piercing terminals in the network plug. The network plug can be inserted into a network socket. Each piercing terminal contacts a corresponding terminal in the socket for transmitting signals through the core wires. Every two core wires of the eight core wires are twisted together to form four pairs of twisted core wires. The first core wire and the second core wire form a twist pair, the third core wire and the sixth core wire form a twist pair, the fourth core wire and the fifth core wire form a twist pair, and the seventh core wire and the eighth core wire form a twist pair. When data (signals) are transmitted in the network, an electromagnetic effect (field) is generated around the core wire. When two core wire are disposed side-by-side, interference may occur between two adjacent core wires except that complementary effect occurs between the adjacent first and second core wires, the adjacent third and sixth core wires, the adjacent fourth and fifth core wires and the adjacent seventh and eight core wires. The interference may affects the transmission in a pair of adjacent piercing terminals configured to be connected to a network socket, especially for the piercing terminals connected to the twist pair of the fourth and fifth core wires, and they may be affected by the interference occurred between the third core wire and the fourth core wire and the interference occurred between the fifth core wire and the sixth core wire to have larger crosstalk and influence the quality of signals when the network plug is connected to a high frequency network.
The network cable includes four pairs of twisted core wires, and the first pair includes a white-orange core wire and an orange core wire, the second pair includes a white-green core wire and a green core wire, the third pair includes a white-blue core wire and a blue core wire, and the fourth pair includes a white-brown core wire and a brown core wire. The wiring of the cable follows T568A or T568B wiring scheme, and the core wires are arranged in an order as follows, white-orange, orange, white-green, blue, white-blue, green, white-brown and brown. The second pair core wires and the third pair core wires are not arranged as the T568A or T568B wiring scheme. This is the reason that crosstalk occurs.
There are eight metal sheets disposed at a tip of the network plug, and the core wires are connected to the metal sheets when the core wires are mounted into the network plug. Because the core wires are arranged side-by-side and the second pair of twisted core wire and the third pair of twisted core wires are not follow the wire scheme, the electrical characteristic is reduced. There are many compensation method for electrical characteristics disclosed by U.S. Pat. Nos. 5,628,647 or 6,409,544 to crosses the twisted pair or separate the second pair of twisted core wires from other wire pairs.
In addition, U.S. Pat. Nos. 7,540,789 and 6,007,368 disclose another compensation methods using the metal sheets of different shapes. U.S. Pat. Nos. 6,116,943 and 6,113,400 disclose compensation methods using circuits on a printed circuit board.
Although the patents mentioned above disclose compensation methods for the wire pairs, the metal sheets have complicated shapes as disclosed in U.S. Pat. No. 6,007,368. The compensation method using printed circuit board may causes over-intensive circuits on the printed circuit board and result in manufacturing problems.